Such data storage media are, for example, chip card controllers which, in a highly developed embodiment, have large flash memories. Current memories have a capacity of several 100 kB. Future generations of chip cards will even have memory units in the MB range.
The more complex and the more extensive the data storage media become, the higher the outlay on functional and quality tests when producing the data storage media.
Special test devices which can simultaneously test and personalize a plurality of data storage media are used to test and personalize the data storage media. The more data storage media can be simultaneously tested and personalized, the lower the costs incurred as a result of the tests and personalization.
A first problem in terms of time spent on the tests and personalization is the possibly low data transfer rate of the interface, in particular if the interface with contacts has been configured in accordance with the corresponding ISO standard for chip cards. The lower the data transfer rate, the longer the test and personalization and the more expensive this operation.
A first possible way (disclosed in the prior art) of reducing the costs of the tests and personalization is therefore to use testers having more test channels so that more data storage media can be simultaneously tested and personalized. However, larger testers are more expensive and are available only with up to a particular number of test channels.
In order to reduce the test and personalization time in the available testers, it is possible to increase the transmission rate of the interface with contacts. However, the maximum transmission rate is limited by the baud rate of the interface used. In order to accelerate personalization, in particular, it is known, for example from the products SLE66 and SLE88 from Infineon Technologies AG, to use a higher external clock frequency for personalization than is provided for in ISO 7816 which is decisive here. In addition, the minimum division factor can be reduced.
Increasing the frequency of the external clock signal further is problematic because neither the test devices nor the contacts are set up for this. Added to this is the fact that data storage media often have sensors which cause the circuit to be reset or data storage medium components to be destroyed in the case of an excessive external clock frequency since it is assumed that a third party is attacking the data storage medium.
However, increasing the frequency of the external clock signal further could not reduce the personalization time of a data storage medium to an unlimited extent either since the personalization time is limited by the programming time of the flash memory if such a memory is used. Increasing the transmission rate further would not, therefore, lead to a reduction in the personalization time.